In the past there have been a number of attempts to produce various types of firearms with interchangeable barrels. Most of this effort has been concentrated on shotguns designed to accommodate different barrels. Some of these attempts are shown in U.S. Pat. Nos. 4,989,359 and 2,529,733. However, with shotguns, being area-fire weapons, there was not great concern about small variations in fit of the barrel which effect accuracy. Also, there have been attempts to place interchangeable barrels on pistols, together with interchangeable cylinders, as shown in U.S. Pat. No. 4,297,801.
An attempt to provide a rifle with interchangeable barrels is shown in U.S. Pat. No. 3,611,611, which requires the use of a concentric sleeve over the barrel to provide a rifle with an interchangeable barrel. This system suffers the disadvantages that it is complex and there is the possibility for slack between the rifle barrel and the sleeve, which can affect accuracy each time a barrel is removed and replaced.
There has been a continuing need to provide a rifle with interchangeable barrels which are both easily and quickly changed while maintaining accuracy of the weapon. The present invention provides a rifle with interchangeable barrels which conserves cost, allows the shooter to use one stock with which he is familiar and comfortable, and provides comparable weight and balance to the total firearm even when the different barrels are attached. All these factors are believed to be helpful to maintaining accuracy by allowing the shooter to maintain the same feel and touch, even though different caliber barrels are utilized. A major shortcoming of prior attempts to provide an interchangeable barrel for a rifle has been to achieve alignment of the barrel and sight system to maintain accuracy. Thus, interchangeable barrels have been successful in shotguns because minor variations in accuracy do not have much effect with these area-fire weapons. Interchangeable barrels or barrel inserts have found some use with pistols, but again in uses where accuracy is not a paramount concern. There has not been a successful large bore hunting rifle which uses interchangeable barrels. It is believed that this is directly attributable to difficulties with zeroing the weapon each time the barrel is changed. The present invention now permits use of interchangeable barrels for rifles which do not require rezeroing the weapon each time the barrel is changed.
Thus, the present invention satisfies a long-felt need and offers substantial advantages to the shooter. These advantages include being able to use the same stock assembly trigger housing and bolt guide configuration for the different barrels. Thus, the shooter continues to utilize the basic components with which he is familiar and comfortable. When the weapon is shouldered, it will come to his accustomed shooting position, unlike using separate rifles of the desired caliber where variations in stock length, shape and thickness require an adjustment for each different rifle. Also, the shooter has the advantage of being familiar with the same trigger pull and bolt action, thus further enhancing consistent habits which improve marksmanship. The rifle of the present invention also has the advantage that for a single stock assembly, a number of different rifle calibers may be used, thus allowing a hunter to take one stock and several barrels in a convenient-sized case for air travel to hunt large game and small game on one trip without the need to carry two or three different complete firearms in bulky containers such as long rifle cases which are frequently over four feet in length. The rifle of the present invention also offers the advantage that the system and mechanism for achieving the interchangeability of the barrels, each with its own sight system, allows the consistent return to zero each time the barrel is removed and replaced. Thus, the shooter only needs to zero the barrel initially. After that, the mounting mechanism allows the barrel to be removed and replaced without the need to rezero the rifle when barrels are changed. Thus, for example, when the hunter is on a trip in the wilderness, he may change barrels without the need to rezero the barrel. Without this feature, interchangeable barrels are not practical for the hunter, as many times he does not have the facilities, targets and other equipment necessary to accurately rezero the barrel while in the field.